Flanges are commonly used in pipe (tubing) to provide additional strength and supporting area, and also to provide an enhanced means for joining together separate sections of pipe. The pipe may be deformed to form a flange as part of the pipe or, alternately, separately manufactured flanges may be joined to pipe sections by welding, threading, brazing, gluing, or other means, depending on desired configurations and the type of pipe and flanges being used.
In the case where flanges are used for joining pipe sections together, mating flanges on the ends of the pipes (where a joint is to be formed) are typically assembled together to join the pipe sections by aligning bolt holes in each flange and bolting the flanges together. It is not uncommon to use anywhere from two to twenty-four bolts for joining flanges used with industrial piping having dimensions of between 1/2" and 24" diameter. A common problem in using bolted flange pipe connections is the potential for stripping bolt or nut threads which causes excessive repair and assembly time. In certain cases, the pipe flanges are seal welded around the perimeter of the joint prior to bolting in order to create leakproof joints. Thus, it is clear that the flange assembly process is often cumbersome and time consuming.
These noted drawbacks of conventional, bolted flanges are especially undesirable when a flanged joint is located in a hazardous area, such as extreme temperature ranges or weather conditions, under water, radiation areas, and toxic gas or material environments. Obviously, such common flange assembly problems can be detrimental to the flange worker in these hazardous areas.
One solution to some of these flange assembly problems is disclosed in U.S. Pat. No. 4,718,698, issued to Hill. Hill discloses an apparatus and method of forming a fusion welded butt joint between thermoplastic pipe sections. The apparatus comprises a pair of insert sleeves made of a thermoplastic material (e.g., polyethylene) which melts and fuses with thermoplastic pipe sections. The apparatus also includes a coupling collar, formed of polyethylene, that surrounds the pipe section joint and sleeves. Imbedded in the coupling collar is a heater coil that raises the temperature of the thermoplastic material to its melting point to fuse the adjacent surface of the coupling collar, pipe sections, and sleeves, to form a homogenous welded joint.
One disadvantage of the Hill patent coupling connection is that it is only useable with thermoplastic pipe and not metal pipe. Another disadvantage is that separate sleeve inserts of similar thermoplastic material must be used to form the homogeneous bonded connection. Furthermore, and most importantly, the coupling connection is not reusable.
Accordingly, objects of the present invention are to overcome the aforementioned prior art problems by providing a remotely operable, reusable, easy-to-use, flange system for pipes.